Inflatable packer

ABSTRACT

An elongated tubular body, connected with a well string in a borehole, telescopically receives a centrally bored mandrel having an annular flange forming a piston slidable in a fluid containing reservoir formed between the wall of the body and mandrel. A dilatable and collapsible member surrounding and connected to the body intermediate its ends defines an inflation chamber communicating with the fluid reservoir. Spring means, surrounding the tubular mandrel, normally urges the mandrel and body in telescopic extended relation.

United States Patent 2,671,510 3/1954 Slick et a1. 166/187 2,741,3134/1956 Bagnell 166/187 2,942,669 6/1960 Mounce et al. 166/187 3,032,1165/1962 Barry 166/187 3,134,441 5/1964 Barry et a]. 166/187 PrimaryExaminerJames A. Leppink AttorneyRobert K. Rhea ABSTRACT: An elongatedtubular body, connected with a well string in a borehole, telescopicallyreceives a centrally bored mandrel having an annular flange forming apiston slidable in a fluid containing reservoir formed between the wallof the body and mandrel. A dilatable and collapsible member surroundingand connected to the body intermediate its ends defines an inflationchamber communicating with the fluid reservoir. Spring means,surrounding the tubular mandrel, normally urges the mandrel and body intelescopic extended relation.

PATENTED APR20 1971 NVEN To/a HAROLD E. SH i LLANDER INFLATABLE PACKEDBACKGROUND OF THE INVENTION 1. Field of the invention.

The present invention relates to inflatable devices and moreparticularly to an inflatable packer for oil wells, or the like.

Inflatable packers are used in the oil well industry for forming a sealbetween the pipe string and wall of the casing or borehole to seal offformation zones and for various other purposes well understood in theoil industry.

The principal advantage of the inflatable packer over a conventionalsolid rubber or resilient material type packer is the ability to expandto a relatively larger diameter; form a seal with an irregular boreholewall surface; and withstand higher pressure differential without aflowing" of the packer material.

2. Description of the Prior Art.

Some of the inflatable packers, as shown by the prior art, utilize thefluid in the well inside or outside of the well string or within thecasing to inflate the packer. This is accomplished by interrupting thecirculation of fluid through the well string to build up a differentialpressure by a pump at the well surface so that a valve, closed, as forexample, by dropping a ball down the well string, actuates the packerfor inflation by the fluid.

Other prior art packers employ a downhole hydraulic pump having anindependent reservoir of fluid wherein the pump is actuated forexpanding the packer by manipulating the pipe string.

The most pertinent devices shown by the prior art include the US. Iats.No. 2,741,313 to Bagnell; No. 2,633,200 to Irlumason and No. 3,032,1l6to Barry.

This invention eliminates the necessity of valve means for initiatingand releasing the packing action and is accomplished by longitudinaltelescoping movement of its components operating a closed hydraulicsystem.

SUMMARY OF THE INVENTION An elongated sleevelike body is connected witha well string in a borehole. An elongated tubular mandrel is slidablyreceived and secured within the body. An annular flange, on the mandrel,forms a piston slidable within a fluid containing reservoir between thewall of the body and mandrel. A dilatable member longitudinallysurrounds and is connected with a portion of the body to form aninflation chamber.

Spring means surrounds the mandrel below the body and normally urges themandrel and body in extended telescopic relation.

The principal object of this invention is to provide an inflatablepacker for connection with a well string in a borehole and means forexpanding and collapsing the packer by telescopic movement of itscomponents.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERREDEMBODIMENTS Like characters of reference designate like parts in thoseFIGS. of the drawings in which they occur.

In the drawings:

The reference numeral It) indicates the device, as a whole, which iscylindrical in general configuration adapted to be connected with a wellstring 12 and run into a borehole indicated by the casing 14. The device10 includes a sleevelike body portion I6 threadedly connected at itsupper end with a tool joint 18 in turn threadedly engaged with the wellstring I2. An elongated tubular mandrel 20 is telescopingly received byits upper end portion by the inner wall surface 22 forming the bore ofthe body 16. The bore 24 of the mandrel 20 is substantially equal to thebore 26 of the tool joint 18 and forms a continuation of the flowpassage, not shown, of the well string I2. The depending end portion ofthe body is circumferentially enlarged to form a cylindrical wallportion 28 surrounding the mandrel 20 in spaced relation therewith toform a fluid containing reservoir 30 and define an annular body shoulder32. The mandrel 20 is provided with an annular flange 34 forming apistonlike portion slidably contacting the inner surface of the wall 28.A lock ring 36, loosely surrounding the mandrel below the flange 34, isthreadedly engaged with the depending end of the wall 28 to maintain themandrel within the body 16.

A dilatable and collapsible packer element 38, formed of reinforcedresilient material, such as rubber or the like, surrounds anintermediate portion of the body above its shoulder 32 and is securedthereto by inserting one end portion of the member 38 into an annulargroove 40 formed in the shoulder 32. The other end of the member 38 issimilarly secured within an annular groove 42 formed in a collarlikering 44 slidably surrounding the periphery of the body 16 whichcompensates for longitudinal contractile action of the member 38. Anysuitable means may be used for maintaining the respective end portionsof the member 38 within the grooves 40 and 42. The member 38 and slidingring 44, in combination with the body I6, thus forms an inflation orexpandable chamber 46 which communicates with the reservoir 30 by aplurality of circumferentially spaced slots or wall ports 48 formedthrough the body shoulder 32.

The reservoir 30 and chamber 46 are filled with a selected fluid S0. Thedimensions of the reservoir 30, in combination with the chamber 46, aresuch that the volume of fluid 50 contained therein will be sufficient todilate the member 38 as hereinafter explained. The reservoir 30 andchamber 46 are maintained fluidtight to prevent loss of fluid 50 byO-rings 52 disposed in suitable grooves formed on the periphery of theupper end portion of the mandrel 20, on its pistonlike flange 34 and theinner surface of the ring 44.

The depending end portion of the mandrel 20 is provided with an enlargedportion forming an annular shoulder 54. A helical spring 56 surroundsthe depending end portion of the mandrel between its shoulder 54 and thebody connected lock ring 36. The purpose of the spring 56 is to normallymaintain the mandrel and body in extended telescoped relation so thatthe packer member 38 will be normally maintained in collapsed position,as shown in FIGS. 1 and 3. The depending end of the mandrel 20 isprovided with threads 58 forming a tool joint for connection withtubular members 12A forming a part of or a continuation of the wellstring 12. Obviously the sliding surfaces of the mandrel 20 and body 16may be keyed or splined for rotating the mandrel.

OPERATION In operation the device is run into a borehole or the casing114 and supported by the well string 12. The mass of the dependingportion of the string 12A, in cooperation with the expansive action ofthe spring 56 and compressive force of fluid in the borehole annulus,normally maintains the packing member 38 in collapsed position. When itis desired to expand the member 38, into sealing relation with thecasing 114 or a borehole wall, the depending end portion of the wellstring ll2A is set down on the bottom or a suitable bridge formed in theborehole, neither of which are shown, so that further lowering of thewell string 12 telescopes the body 16 downwardly over the upper endportion of the mandrel 20 thus moving the shoulder 32 toward thepistonlike flange 34.

The spring 56 is being compressed during this action and the fluid 50,within the reservoir 30, is forced through the ports 48 and into thechamber 46 which forcibly distorts and dilates the member 38 intocontact with the inner wall surface of the casing 14 thus forming afluidtight seal therewith. This setting down or pushing" action of thebody 16 over the mandrel 20 utilizes the mass of the well string 12 toincrease hydraulic pressure into the chamber 46 and an efficientexpanding action of the member 38. However, it seems obvious that theposition of the reservoir 30 and chamber 46 may be inverted so that alift or pull" on the wall string 12 would similarly force the fluid 50out of the reservoir 30 and into the chamber 46 to expand the member 38.To achieve this it would be necessary to use expandable slips connectedwith the well string portion 12A, which are normally set and released bya rotative action of the well string, to maintain the mandrel 20 rigidwhile the lift or pull" action is performed. When it is desired torelease the packer, the member 38 is collapsed by simply lifting thewell string 12 wherein the body 16 longitudinally slides along themandrel 20 until the lock-ring 36 again contacts the pistonlike flange34. This repositions the wall surfaces forming the reservoir 30 to theposition shown by FIG. 3, wherein reduced pressure within the reservoir30 draws or pulls" the fluid out of the chamber 46 to allow theresilient member 38 to return to its collapsed position. This packersetting and releasing action may be repeated as often as desired.

Repeated distortion of the member 38 may tend to prevent its returningto the desired position shown in FIG. 3, however, to more nearly achievethis action a helical spring, not shown, may be interposed in thechamber 46 to bear against the adjacent surface of the shoulder 32 andsliding ring 44.

Obviously the invention is susceptible to changes or alterations withoutdefeating its practicability, therefore, I do not wish to be confined tothe preferred embodiment shown in the drawings and described herein.

1 claim:

1. An inflatable packer, comprising:

an elongated tubular body adapted to be connected with a well string andlowered in a borehole;

a tubular mandrel telescopically received by the inner wall surface ofsaid body, one end portion of said body being circumferentially enlargedto define an outwardly projecting annular shoulder and a cylindricalwall surrounding an intermediate portion of said mandrel in spaced-apartrelation forming a fluid containing reservoir between said body and saidmandrel;

a pistonlike wall formed on the periphery of said mandrel and slidablyreceived longitudinally by the inner surface of said cylindrical wallfor movement toward and away from said annular shoulder duringtelescopic movement of said mandrel;

a lock ring surrounding said mandrel on that side of its pistonlike wallopposite said annular shoulder and coaxially connected with the endportion of said cylindrical wall opposite said annular shoulder;

a cylindrical ring slidably surrounding the end portion of said bodyopposite said lock ring; and

a flexible and expandable cylindrical member longitudinally surroundingsaid body in circumferential spaced relation and connected, at itsrespective end portions, with said annular shoulder and said cylindricalring for forming an inflation chamber, said annular shoulder havingports providing communication between the reservoir and the inflationchamber, whereby fluid is forced from the reservoir into the inflationchamber in response to telescopic movement of said mandrel into saidbody for expanding said flexible member into sealing relation with thewall forming the borehole.

2. Structure as specified in claim 1 in which the end portion of saidmandrel opposite said body is circumferentially enlarged to form amandrel shoulder facing toward said body, and a spring interposedbetween said mandrel shoulder and said lock ring for urging said bodyand said mandrel toward an extended telescopic relation.

1. An inflatable packer, comprising: an elongated tubular body adaptedto be connected with a well string and lowered in a borehole; a tubularmandrel telescopically received by the inner wall surface of said body,one end portion of said body being circumferentially enlarged to definean outwardly projecting annular shoulder and a cylindrical wallsurrounding an intermediate portion of said mandrel in spaced-apartrelation forming a fluid containing reservoir between said body and saidmandrel; a pistonlike wall formed on the periphery of said mandrel andslidably received longitudinally by the inner surface of saidcylindrical wall for movement toward and away from said annular shoulderduring telescopic movement of said mandrel; a lock ring surrounding saidmandrel on that side of its pistonlike wall opposite said annularshoulder and coaxially connected with the end portion of saidcylindrical wall opposite said annular shoulder; a cylindrical ringslidably surrounding the end portion of said body opposite said lockring; and a flexible and expandable cylindrical member longitudinallysurrounding said body in circumferential spaced relation and connected,at its respective end portions, with said annular shoulder and saidcylindrical ring for forming an inflation chamber, said annular shoulderhaving ports providing communication between the reservoir and theinflation chamber, whereby fluid is forced from the reservoir into theinflation chamber in response to telescopic movement of said mandrelinto said body for expanding said flexible member into sealing relationwith the wall forming the borehole.
 2. Structure as specified in claim 1in which the end portion of said mandrel opposite said body iscircumferentially enlarged to form a mandrel shoulder facing toward saidbody, and a spring interposed between said mandrel shoulder and saidlock ring for urging said body and said mandrel toward an extendedtelescopic relation.